Harlot [3.0] Overview

The Harlot [3.0] is the definitive version of the most popular 3D printed handgun ever released. Originally developed by BAD-CAD and refined by the Black Lotus Coalition, the Harlot has been through multiple iterations. Version 3.0 (also known as the “Harlet”) combines all the best upgrades into one package: improved ergonomics, a reinforced steel dime breech, better sights, a smoother trigger, and an easier-to-use barrel latch.

This is still a single-shot, break-action .22LR derringer at heart. But everything that made the original Harlot good has been made better. If you’ve built a V1 or V2, the Harlot [3.0] is a noticeable step up. If this is your first 3D printed firearm, you’re starting with the best version.

The Harlot [3.0] Build Kit includes every non-printed component you need: a pre-chambered 2″ rifled barrel liner, all hardware with extras, springs, and a pre-drilled steel dime for the reinforced breech. Print the files, open the kit, assemble.

What’s New in Harlot [3.0]

Steel Dime Breech
The biggest upgrade in the Harlot [3.0] is the reinforced breech. Instead of relying on printed plastic to contain chamber pressure, V3 uses a pre-drilled steel dime as a breech face. This is a significant safety and durability improvement over earlier versions, and the kit includes the dime already drilled and ready to install.

Larger Frame, Better Grip
The Harlot [3.0] features an enlarged frame compared to V1 and V2. More material means a better grip, improved control during firing, and a more comfortable shooting experience. The derringer is still compact, but now it actually fits your hand.

Improved Barrel Latch
Breaking open the action on earlier Harlots could be finicky. The V3 barrel latch mechanism has been completely redesigned for smoother, more reliable operation. Open, load, close, fire. No fighting with the mechanism.

Better Trigger and Sights
The Harlot [3.0] includes an improved trigger design for a cleaner break. Sights have also been refined for easier target acquisition. Small changes that make a noticeable difference at the range.

Longer Barrel
V3 uses a 2″ barrel liner (up from the original 37mm). The extra length improves accuracy and provides a more complete powder burn, resulting in better velocity from the .22LR cartridge.

Harlot [3.0] FAQ

Is the Harlot [3.0] Build Kit a complete firearm?

No. The Harlot [3.0] Build Kit contains hardware, springs, and barrel components only. You must 3D print the frame, grip, and other structural components separately using files from the Black Lotus Coalition or DEFCAD.

Where do I get the Harlot [3.0] print files?

The Harlot [3.0] (Harlet) STL files are available from the Black Lotus Coalition and DEFCAD. We do not distribute the print files directly. Search for “Harlet V3” to find the correct version.

What’s the difference between Harlot V1, V2, and V3?

The Harlot [3.0] includes significant improvements over earlier versions: a steel dime breech for reinforced chamber containment, a larger frame for better grip, redesigned barrel latch for smoother operation, improved trigger and sights, and a longer 2″ barrel. If you’ve built earlier versions, V3 is a meaningful upgrade.

What printer do I need to build the Harlot [3.0]?

Any standard FDM printer with a typical build volume will work. The Harlot [3.0] was designed to print on entry-level machines without specialized modifications. PLA or PLA+ filament is recommended (Esun PLA+ is popular in the community).

What are the recommended print settings for the Harlot [3.0]?

Print the breech block at 99% infill. All other parts should use at least 6 walls, 6 top/bottom layers, and 15% infill with a 3X line multiplier. Do not use supports or brims. Consult the README included with the print files for complete settings.

What is the dime breech?

The dime breech is a steel reinforcement for the breech face. Instead of relying on printed plastic to contain chamber pressure, the Harlot [3.0] uses a pre-drilled dime as a steel backing. This kit includes the dime already drilled and ready to install.

Is the Harlot [3.0] legal to build?

Under federal law, individuals may manufacture firearms for personal use without a license. However, state and local laws vary significantly. Some jurisdictions prohibit home-built firearms entirely. It is your responsibility to verify the laws in your area before ordering.

What is the UFA grip weight option?

Federal law (the Undetectable Firearms Act) requires handguns to contain a minimum of 3.7oz of metal. The optional UFA grip weight is designed to meet this requirement. If you prefer to add your own metal weight, select the option without the grip weight.

Can I sell a Harlot [3.0] I build?

Manufacturing firearms with the intent to sell requires an FFL. Building for personal use is legal federally; building for sale is a licensed activity. This kit is intended for personal use only.

Legal Compliance

The Harlot [3.0] is designed for legal home manufacture under federal law. Key compliance features:

Rifled Barrel: Kit includes a rifled .22 barrel liner. Using a smoothbore tube may classify the firearm as an AOW under the NFA. Always use the rifled liner provided.

Metal Weight Requirement: Federal law (UFA) requires handguns to contain a minimum of 3.7oz of metal. The optional UFA grip weight is available to meet this requirement. Builders are responsible for ensuring compliance.

State Laws Vary: Some states prohibit home-manufactured firearms. Know your local laws before ordering the Harlot [3.0] Build Kit.

Components

QTY	ITEM
1×	.22LR Barrel
1×	Gun Spring
1×	Compression Spring

Hardware

QTY	ITEM
8×	M3x20mm Button Head Screw
6×	M3 Nut

Tools

QTY	ITEM
1×	USB w/ Files
1×	M3 Hex Key

Additional information

Weight	1 lbs
Dimensions	10 × 10 × .5 in

Harlet [3.0] Build Kit